Are there any actions I can hook into for update_post_meta()? I don't see anything obvious in the source. Woocommerce lets you change the featured status of items via ajax from the edit screen. I am using a transient to store the featured items in lieu of querying them every time and I'm deleting that transient on the save_post hook, but it isn't getting fired because of the ajax function that directly updates the post meta. Worst case I can unhook woo's action and recreate it myself with the delete transient call, but I'm wondering if there is another hook i could use.